This invention relates generally to leak resistant drinking cups and more particularly to a leak resistant drinking cup having a diaphragm that is moveable between a sealed position and an unsealed position.
Leak resistant drinking cups are often adapted for use by young children (e.g., infants, toddlers, preschoolers). These types of drinking cups are configured so that when they are turned over, liquid inside the cup is prevented from spilling out of the cup by a valve or valve assembly. Usually, the cup includes a container with an open top for receiving and holding liquids therein and a relatively rigid cover for closing the open top of the container. A spout is typically formed as one-piece with the rigid cover for allowing a child to drink from the cup. The cover can be releasably attached (e.g., snapped or screwed on) to the container.
The valve or valve assembly is typically disposed between the cover and the container and can be moved from a closed, sealing position to an opened, unsealing position to allow liquid to pass out of the cup for drinking. Most commonly, the valve is actuated by a vacuum pressure applied by the user to the interior of the cup by sucking on the spout. The applied vacuum pressure causes the valve to move or otherwise deform in such a way (i.e., move toward the spout) that a path past the valve is exposed so liquid can flow out of the cup. It is possible that the valve might be actuated in other ways, such as a purely mechanical actuation, but for young children vacuum pressure actuation is most preferable because the only time the valve is open is when the child is in the act of taking a drink.
Vacuum pressure actuated drinking cups of the type just described have certain problems generally associated with balancing the need to assure positive sealing with the need to make the cup easy to use for the child. A strong seal by the valve requires a relatively large vacuum to open, making it hard for the child to use. A valve having a seal that requires a lower vacuum pressure to open may not seal tightly enough to prevent at least some liquid flowing past it, especially when dropped, swung, shaken, or impacted. Thus, valves having low vacuum pressure actuated seals are typically prone to leak.
Frequently, conventional valves are relatively small and located under the spout. These types of valves often require a substantial vacuum pressure to actuate because the pressure acts on only a relatively small area of the valve. In other words, children will have to suck with significant effort to get the valve to open and obtain a drink, which makes the cup less desirable to the child.
In one conventional configuration, the valve or valve assembly can be permanently attached to the cover. During normal use of the cup, the valve or valve assembly will become fouled with liquid and particulates in the liquid. Although cleaning is possible, it is very difficult to clean the entire valve/valve assembly or the entire cover. Disassembly of the valve/valve assembly from the cover in this type of configuration would result in destruction of the valve/valve assembly or cover. As a result, it is difficult for caregivers to provide the child with a drinking cup that has a clean valve/valve assembly and cover in repeated uses of these types of drinking cups.
In another conventional configuration, the valve or valve assembly can be disassembled from the cover for cleaning. Even with the capability of being disassembled for cleaning, some known valves and valves assemblies are still prone to fouling. Some valves and valve assemblies are difficult to detach and reassemble as they require precise alignment or orientation. Moreover, small valves or pieces of a valve assembly may be easily lost or pose a danger to the child if the cup becomes disassembled.